Patent EP-0126439-A2 (EP)
Inventor: WEGMANN GERHARD ING GRAD
IPC: H04M7/00
Filed: 1984-05-17
Abstract: 1. A telecommunications network, in particular a telephone network, comprising groups of connection lines which interconnect network nodes and form network branches, and comprising network internal exchanges which are arranged at the network nodes and which, individually in respect of each connection, interconnect connection lines of different groups for selected connections, and comprising peripheral exchanges in the network branches, and comprising a hierarchical structure, by means of which peripheral exchanges are connected in groups via a star network of groups of connection lines (direct (first-choice) routes, last-choice routes) to a network internal exchange, which is provided in respect of each group of peripheral exchanges and is commonly assigned thereto, of a network level super-imposed upon the peripheral exchanges, and by which network internal exchanges are directly connected to one another by a meshed network of groups of connection lines and/or are connected, likewise in groups, by a further star network of groups of connection lines to a network internal exchange, which is provided in respect of each group of network internal exchanges of the superimposed network level and again is commonly assigned thereto, of at least one even higher network level, and comprising direct line groups which deviate from this network hierarchy and which directly interconnect - and thus at least partially intermesh - the exchanges of the different network levels, and for the use of which lower limit values are imposed for traffic values or line numbers, where, on the basis of factors of economy, on the one hand when individual lines are used in respect of each direct connection line group said limit values are governed by the requisite connection of a line path, and on the other hand when transmission systems are used comprising a common transmission line for a system-related number of channels (one channel for each of the two transmission directions) said limit values are governed by this number, where one channel pair in each case corresponds to one connection line, characterised in that a direct line traffic relationship between the periperal exchanges and network internal exchanges of two groups of such exchanges is generally limited inasmuch as those direct line groups which interconnect different network levels (transversal direct line groups) extend only between the exchanges of the first group, which form the peripheral exchanges and network internal exchanges, and the network internal exchange of the other group which is common to the peripheral exchanges of the other group and thus is assigned to the next higher network level, and/or the network internal exchange of the other group which is common to the respective other group of network internal exchanges and is thus assigned to the next higher network level, and that these direct line groups serve not only to establish connections from the exchanges of the first group to those of the other group, but also to establish connection in the reverse direction, whereby in the vent of a connection establishment procedure between the first group and the other group via a direct connection line of the respective direct line group, this line is seized in an ascending direction in respect of the mutually superordinated network levels, and in the case of a connection establishment procedure from the other group to the first group via one of these direct connection lines, this line is seized in the descending direction.